Potentiometric Sensor for the Determination of Lead(II) Ion Based on Zirconium(IV) Iodosulphosalicylate

Zirconium(IV) iodosulphosalicylate (ZIS), a cation exchanger, was synthesized by mixing 0.1 M zirconium oxychloride to a mixture of 0.1 M 5-sulphosalicylic acid and 0.1 M potassium iodate at pH 1. The distribution coefficient values of various metal ions were determined at pH 6 which showed high selectivity for Pb(II) ion. Due to its Pb(II) selective nature, the ion-exchanger was used as an electroactive material for the preparation of an ion-selective membrane electrode. The membrane (M - 1) was characterized by XRD and SEM analysis. It was observed that membrane (M - 1) displayed a useful analytical response with excellent reproducibility, low detection limit (4.07 x 10(-6) M), wide working pH range (3-6.5) and quick response time (15 s). The electrode responds to Pb(II) in a linear range from 1 x 10(-5)-1 x 10(-1) M with Nerstian slope of 24 mV per decade change in concentration. The life span of electrode was found to be 90 days. The sensor has been used as indicator electrode in potentiometric titration of Pb(II) ion with EDTA.